RE: ESM P-39
Yes the batteries do fit in through the nose wheel. It's a tight fit, but works fine.
The setup is:
motor: Efltie Power 160
Battery: 2x 6s 5800 mah packs in series
ESC: Castle 110 HV
Prop: APC 20-10
Here's a photo of the battery compartment. It fits nicely behind the firewall. I did have to add about 10 oz. of weight in the tail section to get the CG right.